There are seven different ways to remove bees from buildings. The method you should use depends on whether they’re a swarm or if they’re an established colony within a building.
These are different. A swarm is known as a breakout from the hive. Several bees (50+) will leave an established colony on the honeycomb within a building. The swarm leaves the colony and flies into a bush or a tree and search for a place to establish a new colony.
Therefore, swarm removal is very different to removal from a building of an established colony removal. In a building void, you potentially could have two to three hundred kilograms of honey that has been in there for ten years.